Short-Term Credit Facilities (Narrative) (Details) ZAR in Millions, $ in Millions, ₩ in Billions	3 Months Ended
	Sep. 30, 2016 ZAR	Sep. 30, 2016 USD ($)	Jun. 30, 2016 KRW (₩)	Jun. 30, 2016 ZAR	Jun. 30, 2016 USD ($)
Short-term Debt [Line Items]
Amount utilized						[1]
South African Credit Facility [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity	ZAR 150.0	10.8
Amount utilized	131.1	9.5		ZAR 131.1	$ 8.9
South African Credit Facility [Member] | Nedbank Limited [Member]
Short-term Debt [Line Items]
Aggregate amount	400.0	28.8
Primary amount, available immediately	200.0	14.4
Secondary amount, not available immediately	200.0	14.4
Bank Overdrafts Facility [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity	ZAR 50.0	$ 3.6
Short term interest rate	9.35%	9.35%
Commitment fee percentage	0.35%
South Korea, Hana Bank Overdraft Facility [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity		$ 9.1	₩ 10
Expiration date	Jan. 01, 2017
Short term interest rate	3.31%	3.31%

[1] Derived from audited financial statements